Do Gps's factor in incline?

My gps and bike computer are always off on distance. I was wondering does a gps factor in the incline and decline of my ride? Or is it just factoring the distance point to point? If it didn't include the fact I was also going up that would make sense why it always show a lower distance then my bike computer.

no, the GPS will not factor slope into the distance traveled. some programs will do that calculation when you download your GPS tracks.

also keep in mind that gps is always going to be a little short on curves. there are two things you can do at this point: 1) use 1sec recording interval when on the mtb and that will minimize it 2) use the speed/cad sensor if your GPS is compatible with it. I'm not sure if the Edge 305 and 705 were updated to always use the speed/cad sensor, but the Edge 500 and Edge 800 do. but if you use auto recording or something else, it will often come up quite short.